Internal combustion engines



Nov. 24, 1959 H.' s. E. JOUCLARD 2,914,049

INTERNAL COMBUSTION ENGINES Filed July 8, 1957 v 2 Sheets-Sheet I Henri 6.5 JOUL'LARD Nov. 24, 1959 v H; G. E. JOUCLARD 2,914,049

INTERNAL COMBUSTION ENGINES Filed July 8, 1957 1 2 Sheets-Sheet 2 III Hem/0.5. Jul/am ATTORNEYS United States Patent INTERNAL COMBUSTION ENGINES Henri Georges Emile Jouclard, Sannois, France Application July 8, 1957, Serial No. 670,461 Claims priority, application France July 20, 1956 Claims. (Cl. 123-48) The present invention relates to an internal combustion engine having means for instantaneously varying the volume of the combustion chamber in accordance with the volume of gas admitted therein, so as to obtain a generally constant compression ratio independently of the rate of admission of gas into the combustion chamber.

Prior devices of this type have as a common feature a movable cylinder end wall in the form of a piston, termed inverted piston; various means have been devised for suitably displacing such inverted piston, among them devices exerting on the outer face of the inverted piston a pressure counterbalancing the internal compression in the combustion chamber, so as to obtain a constant compression ratio.

A defect common to such prior art devices' consists in that no control is exerted on the volume of gas present in the conduit between the carburetor and the cylinder, so that the displacement of the inverted piston is not instantaneously adjusted to the volume of gas admitted to the combustion chamber. It may happen in such a case that the compression ratio becomes too high, whereby engine noise and damages may result.

This and other disadvantages are avoided according to the invention by the use of an inverted piston the displacements of which are rigidly controlled by the movement of the acceleration pedal, so that there is complete correspondence at any instant between the volume of gas supplied by the carburetor and the volume of the combustion chamber; at the same time the displacements of the inverted piston control the opening of the inlet valves and/or of an admission port upstream of the valves, so

that the amount of mixture still present in the intake manifold, which mixture is beyond the control of the carburetor throttle, comes under the control of the inlet valves.

The invention, therefore, in generic terms, consists of the combination of: means to displace the inverted piston, controlled by the opening of the carburetor throttle,-and means to control the opening ofthe admission openings, controlled by the displacement of the inverted piston.

A further important feature of the invention consists in the provision of means whereby the exhaust valvesare always opened completely after each explosion, to allow full evacuation of the spent gases.

The above and other features of the invention will now be described with reference to the accompanying drawings, in which: Figure'lis a longitudinal section of an inverted piston, taken through the plane of both inlet and exhaust valves;

Figure 2 is a section on line IIII of Figure 1; Figure 3 is a section on line IIIIII of Figure 1; K Figure 4 is a schematic view of an inlet manifold with a modified valve;

Figure 5. is a longitudinal section of a cylinder head and inverted piston having means to fully open the .valves. v

1 2,914,049 Patented Nov. 24, 1959 Figure 6 is an elevation of the swinging'plate of the embodiments of Figure 5;

Figure 7 is a section on line VII-VII of Figure 6;

Figure 8 is a longitudinal section of a hydraulic control device; and

Figure 9 is a longitudinal section of another hydraulic control device.

With reference to Figures 1-3 and 5, numeral 1 indicates the cylinder, 2 the motor piston, 3 the cylinder head preferably integral with the cylinder, and 4 the inverted piston, which is displaced as will be explained hereinafter, so as to vary its distance from the motor piston, and to adjust the volume of the combustion chamber in accordance with the rate of admission of gas therein. At full admission rate the inverted piston 4 is farthest removed from the upper neutral position of motor piston 2, while at low admission rate the inverted piston 4 is in its nearest position to the upper neutral position of motor piston 2. The inlet and exhaust valves 5 and 6 are carried by the inverted piston 4.

The control of the position of inverted piston 4 is achieved by means of a hydraulic device actuated by the acceleration pedal, two embodiments of which will be described later, with reference to Figures 8 and 9.

Control of the admission openings of the combustion chamber, in accordance .with the admission rate, may be achieved as follows:

As shown in Figures 1 to 3 the inverted piston 4 is provided with a lateral port 7, which, in the full admission position of the piston 4 registers with a matching port 8 in the cylinder head 3. As the piston 4 is brought to its position of low admission, the two ports are closed gradually, in proportion to the displacement of the piston 4. The port 7 communicates with the inlet valve 5, and port 8 with intake manifold 9; the inverted piston 4 takes a position ranging from admission to 10% or even as low as 4% and provides automatically the adequate percentage of gas admission. The volume of gas which accumulates in the movable conduit between port 7 and the inlet valve 5 substantially equals the smallest possible volume of the combustion chamber.

With such an arrangement, the shafts of the rockerarms (not shown in Figures 1-3) actuating stems 5' of the inlet valves 5, can be fixed to the cylinder head 3, these inlet valves 5 following the motion of the inverted piston 4, that is approaching or being removed from their rocker-arms; at full admission, that is when the inverted piston '4 is remote from themotor piston, the rockerarms are in contact with stems 5' and the valves are opened fully. At low admission the inverted piston 4 is in its position closest to the motor piston; the rocker arms, being remote from the valve stems operate only towards the end of their stroke, thus offering only a small valve opening and consequently a low admission ratio.

Opening of the inlet valves 5 maybe retarded, this offering the advantage of generating, at low admission, an excess vacuum within the cylinder, which makes the combustion more regular; it would be objectionable, however, to advance the closing of the exhaust valves 6, because this would hamper the normal evacuation of the spent gases; the spent gases would remain in the combustion chamber, would be compressed together with new gases admitted for the subsequent combustion, and would prevent ignition.

For this reason, as shown in Figure 2, the exhaust valve 6 communicates with the exhaust pipe (not shown) through a port 10 of the inverted piston 4 and a port 11 of the cylinder head 3, which ports are always fully open, due to the fact that they are much larger than the stroke of the invertedpistomand that port. 11 is larger than port by an amount at least equal to the stroke of the inverted piston.

Furthermore, means are provided whereby the exhaust valves 6 are always fully opened, no matter what the position of the inverted piston 4 may be.

Such means are illustrated in Figures 5 to 7; in Figure 5, numeral 12 indicates the lever displacing the inverted piston 4 through the action of one of the hydraulic systems illustrated in Figures 8 or 9. The lever 12 is attached to a pivotally mounted shaft 13, and for the downward movement of the inverted piston 4 engages the top of said piston while for the upward movement it engages a bracket member 4a, rigidly connected to the inverted piston 4.

The stems 14 of exhaust valves 6 are engaged by rocker-arms 15, the pivotal shafts 16 of which are fixedly mounted on a swinging plate 17, which plate 17 is pivotally mounted on a shaft 18 (Fig. 7). Plate 17 has rigid forks 19 which are engaged by cranks 20 rigidly mounted on the pivotal shaft 13. The swinging plate 17 comprises holes 21 to allow passage of the rods 22, actuating the rocker-arms by means of pivotal attachments 23. The shaft 18 of plate 17 is fixed to the cylinder head 3, and is disposed generally coaxially with the pivotal axes of attachments 23.

With such an arrangement, it will be seen that when the lever 12 rotates with shaft 13, to raise or lower the inverted piston 4, the cranks engage forks 19, to swing plate 17 about shaft 18, thereby raising or lowering correspondingly the shafts 16 of rocker-arms 15, so that the rocker-arms are always kept in contact with stems 14 of the exhaust valves 6, andthese valves are always fully opened. The movement of shaft 16 has no effect on the action of rods 22 on rocker-arms 15, since the pivotal attachments 23 of these rods 22 are generally coaxial with the centre of rotation of shaft 16, namely the axis of shaft 18.

It is also possible to mount the rocker-arms of the inlet valves, as well as of the exhaust valves on the swinging plate 17, so that also the inlet valves 5 are always fully opened, the control of gas admission being obtained exclusively by ports 7 and 8.

The arrangements of ports 7 and 8 of Figure 1 may be replaced by a device such as the one shown in Figure 4, comprising a hollow ball 24 which at low admission is almost in contact with its seat and at full admission is centered in the inlet manifold 25 and offers only a minimum resistance to the passage of gases. The movement of ball 24 is directly controlled by the inverted piston 4, through a shaft 26.

The hydraulic device for controlling the position of the inverted piston will now be described with reference to two embodiments thereof, illustrated in Figures 8 and 9.

With reference to Figure 5, one of the levers 12 mounted on the rotatable shaft 13 has an extension 27, connected to the hydraulic device of Figure 8.

This hydraulic device, which is suitable for multicylinder engines, comprises a cylinder 28 with a piston 29 sliding therein; The piston rod 30 of piston 29 is pivotally connected through a link 31 to lever 27. The lower body portion of the hydraulic device, which is assembled with the cylinder 28 by means of a screw 32, comprises an oil inlet 33 communicating through an inlet valve 34 and a flow-restricting apertured screw 35 with the chamber B of cylinder 28; oil inlet 33 also communicates through a conduit 36 with an oil outlet 37 returning to the oil pump, feeding inlet 33. Oil outlet 37 is in communication through an outlet valve 38 and a flowrestricting apertured screw 39 with the chamber B. In conduit 36 there is disposed a plunger 40 adapted to close communication of oil inlet 33 with oil outlet 37, said plunger 40 being actuated by a cam 41 rigidly mounted on a shaft 42.

The oil outlet valve'38 isconnected to a pusher 43,

actuated by a second cam 44 rigidly mounted on the same shaft 42. A lever 45, connected to the acceleration pedal (not shown) is also rigidly mounted on shaft 42.

Cylinder 28 is closed at the top by a cover 46.

As the explosions take place in the combustion chamber of the engine, the fluid in chamber B is subjected to the pressure on the inverted piston 4 reduced in the ratio of the surfaces of pistons 4 and 29 and of the lengths of levers 12 and 27. Preferably compression springs 47 and/or 47 are interposed between a cap 48 engaging lever 27 and the cover 46, so as to reduce still further the pressure on the fluid; the springs 47 and 47 are calibrated to absorb part of the pressure when ignition takes place, and to resist completely the pressure which occurs at the end of the compression stroke of motor piston 2, before ignition has taken place. In this manner the pressure required in chamber B may be reduced to a value which permits using a 3 kg. pump of the type conventionally used for braking and lubricating purposes.

The hydraulic device operates as follows:

Normally the oil enters at 33, passes through conduit 36 and returns to the pump through outlet 37. As the lever 45 is shifted in one direction it operates cam 41 which raises plunger 40, to close conduit 36. Thereby the pump is loaded, and the pressure opens valve 34 and chamber B is filled at a rate depending on the aperture in screw 35. Pressure in B raises the piston 29 and lowers the inverted piston 4 (Fig. 5) to vmy the volume of the combustion chamber. If the lever 45 is shifted in the opposite direction, cam 44 acts on the pusher 43, to open valve 38, which causes the liquid in B to flow out through outlet 37, at a rate depending on the aperture in screw 39. Thereby piston 29 is lowered and piston 4 is raised, to increase the volume of the combustion chamber.

Figure 9 illustrates a second embodiment of the hydraulic device, suitable for single and multicylinder engines, and in which fluid is supplied to both sides of piston 29. In this embodiment the elements corresponding to those of the hydraulic device of Figure 8 are indicated by the same numerals 29 to 46, followed by the suffix a. The device further comprises a chamber A disposed on the side of piston 29a opposite to chamber C (corresponding to chamber B of Figure 8); chamber A communicates through channel 49, provided with valve 50, and outlet 37a, with the pump. Valve 50 is controlled by pusher 51 and cam 52 mounted on shaft 42a, said cam 52 operating simultaneously with cam 41a. At rest the piston 29a is imprisoned between the fluid in chambers A and C, since valves 34a, 38a and 50 are closed. When the piston 29a is lowered by the action of lever 45a, as in Figure 8, valve 50 is opened by the vacuum in chamber A, and chamber A is filled with fluid. When, on the contrary, piston 29a is raised, valve 50 is opened by cam 52, synchronized with cam 41a, to allow exit of the fluid from chamber A.

Having thus described my invention, what I claim is:

1. In an internal combustion engine having a cylinder, a motor piston slidable therein, a carburetor, means regulating said carburetor and gas inlet and exhaust means for said cylinder; means for automatically adjusting the volume of the cylinder to the volume of gas admitted therein, to obtain a generally constant compression ratio; said adjusting means comprising in combination an inverted piston in said cylinder, means controlled by said carburetor regulating means to axially displace said inverted piston towards or away from said motor piston, respectively as the volume of gas issuing from the carburetor is decreased or increased, and means controlled by the displacement of said inverted piston, to respectively decrease or increase the opening of said gas inlet means.

2. The combination of claim 1, and means to fully open said exhaust means.

3,. In an internal combustion engine having a cylinder, at motor piston slidable therein, a carburetor having a throttle, an acceleration pedal regulating said throttle,

and inlet and exhaust valves for said cylinder; means for automatically adjusting the volume of the cylinder to the volume of gas admitted therein, to obtain a generally constant compression ratio; said adjusting means comprising in combination an inverted piston in said cylinder carrying the inlet and exhaust valves, a hydraulic device, controlled by said acceleration pedal, having means conmeeting it to said invertedpiston to displace the same towards or away from said motor piston respectively as the volume of gas issuing from the carburetor is decreased or increased, a port in the cylindrical wall of said inverted piston communicating with the inlet valve, a port in the cylinder communicating with the carburetor and registering with said first port in the position of the inverted piston remote from said motor piston, said ports having an axial extent substantially equal to the stroke of said inverted piston, another port in said inverted piston communicating with said exhaust valve, a port in said cylinder fully registering with said exhaust port at all positions of said inverted piston, and mechanical means connected to said exhaust valve, to fully open said valve.

4. The combination of claim 3, and means opening said inlet valve to an extent proportional to the position of the inverted piston, said means comprising a rockerarm engaging the stern of said inlet valve, said rockerarm being pivotally mounted on said cylinder, whereby upon movement of said inverted piston the stems of said inlet valves are removed or approach said rocker-arms.

5. The combination of claim 3, said inverted piston exhaust port having an axial extent substantially greater than the stroke of said inverted piston, and the corresponding cylinder exhaust port registering therewith having an axial extent at least generally equal to the sum of the axial extent of said inverted piston exhaust port and the stroke of the inverted piston.

6. The combination of claim 3, said mechanical means connected to said exhaust valve comprising a rocker-arm adapted to engage the stem of the exhaust valve, mounted on a pivotal shaft, a rod pivotally connected to and actuating said rocker-arm, said pivotal shaft being mounted for swinging movement about a second shaft generally,

coaxial with the pivotal connection of said rod to said rocker-arm, said second shaft being mounted on said cylinder, and means mounted on said connecting means between the hydraulic device and the inverted piston, to

swing said pivotal shaft correspondingly to the displacement of the inverted piston, whereby said rocker-arm is constantly in contact with the stem of said exhaust valve.

7. The combination of claim 6, and identical mechanical means connected to the inlet valve.

I 8. In an internal combustion engine having a cylinder, a motor piston slidable therein, a carburetor having a throttle, an acceleration pedal regulating said throttle, and inlet and exhaust valves for said cylinder; means .for automatically adjusting the volume of the cylinder to the volume of gas admitted therein, to obtain a generally constant compression ratio; said adjusting means comprising in combination an inverted piston in said cylinder carrying the inlet and exhaust valves, a hydraulic device, controlled by said acceleration pedal, having means connecting it to said inverted piston to displace the same towards or away from said motor piston respectively as the volume of gas issuing from the carburetor is decreased or increased, a ball valve in said cylinder, communicating with the carburetor, means mechanically connecting said inverted piston with said ball valve to open and close the ball valve upon displacement of said inverted piston, conduit means placing said ball valve in communication with said inlet valve, a port in said inverted piston communicating with said exhaust valve, 21 port in said cylinder fully registering with said exhaust port at all positions of saidinverted piston, and mechanical means connected to said exhaust valve, to fully open said valve.

9. The combination of claim 3, said hydraulic device having a piston acted on by fluid under pressure on only one side thereof.

10. The combination of claim 3, said hydraulic device having a piston acted on by fluid under pressure on both sides thereof.

References Cited in the file of this patent UNITED STATES PATENTS Re. 23,307 Kratzer Dec. 12, 1950 1,521,077 Clegg Dec. 30, 1924 1,754,410 Allwill Apr. 15, 1930 2,686,505 McCuen Aug. 17, 1954 FOREIGN PATENTS 259,168 Germany Apr. 26, 1913 

